sedimentary

Conglomerate

Conglomerate (Sedimentary Clastic Rock)

AI-generated identification · may be incorrect

Hardness: Variable (depending on clast and matrix composition, usually 6-7 if quartz-rich); Color: Grey, tan, or brown matrix with multicolored clasts; Luster: Dull or earthy; Crystal Structure: Clastic (non-crystalline matrix); Cleavage: None; Specific Gravity: 2.6-2.8

Color: Grey, tan, or brown matrix with multicolored clasts
Luster: Dull or earthy

Identified March 31, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the lithification of rounded gravel and boulders. Usually created in high-energy environments like fast-moving rivers or beaches where water rounds the stones. They range in age from Precambrian to Cenozoic.

Uses & applications

Predominantly used as architectural stone, coarse aggregate in the construction industry for concrete, and occasionally as an ornamental stone in landscaping or interior design.

Geological facts

Conglomerates are like a geological 'time capsule,' often containing different types of rocks from many different upstream sources. On Mars, the Curiosity rover discovered conglomerate outcrops, proving the existence of ancient riverbeds on the Red Planet.

Field identification & locations

Identify in the field by looking for rounded, water-worn pebbles larger than 2mm embedded in a finer-grained matrix. Found globally in ancient riverbeds, alluvial fans, and coastal regions. Collectors look for 'puddingstone' varieties with contrasting colors.